Jerry is a fun guy to watch and I am in agreement for the most part with what he demonstrated in the first posting. But the animals that have heavy bone structure or larger bones can stop a bullet that expands or breaks up. If that happens, the bullet will not get in where they live. And even if it makes it inside, the energy could then be expended and it will not penetrate and disrupt tissue.
Elmer Keith related that the test of bringing down an elephant is using a caliber and power that can break the near leg and penetrate through to take out the massive heart. A central nervous system KO brain shot is no real test of a caliber cartridge and its power according to Elmer Keith. He was Big-Bore before Big-Bore was cool.